Feature: Add method for querying toVertex/fromVertex and steps

[kcmvp]

right now I haave two cases, which dont have simple way to ahieve
1: query all the direct vertexs( from vertexes) to a specified Vertex
2: query all the direct vertexes(target Vertexs) from a specified Vertex.

there may be similar requirements for different steps, so hope it supplies two method

1: Vertexes.To(hash K, steps int) []Vertex
1: Vertexes.From(hash K, steps int) []Vertex

[davemcphee]

It sounds like PredecessorMap and AdjacencyMap already do this. Both return a map[K]map[K]Edge[K] of incoming (for PredecessorMap) and outgoing (for AdjacencyMap) Edges.

Edges have a Source and Target, so you can grab the corresponding Vertices from the Graph using either of those.